Issue 1848 - Clean up local reference handling

jni/JniWebRequest.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 24 matching lines @@
   : JniCallbackBase(env, callbackObject), AdblockPlus::WebRequest(),
     tupleClass(new JniGlobalReference<jclass>(env, env->FindClass(PKG("HeaderEntry")))),
     serverResponseClass(new JniGlobalReference<jclass>(env, env->FindClass(PKG("ServerResponse"))))
 {
 }
 
 AdblockPlus::ServerResponse JniWebRequest::GET(const std::string& url, const AdblockPlus::HeaderList& requestHeaders) const
 {
   JNIEnvAcquire env(GetJavaVM());
 
-  jclass clazz = env->GetObjectClass(GetCallbackObject());
-  jmethodID method = env->GetMethodID(clazz, "httpGET", "(Ljava/lang/String;Ljava/util/List;)" TYP("ServerResponse"));
+  jmethodID method = env->GetMethodID(
+      *JniLocalReference<jclass>(*env, env->GetObjectClass(GetCallbackObject())),
+      "httpGET", "(Ljava/lang/String;Ljava/util/List;)" TYP("ServerResponse"));
 
   AdblockPlus::ServerResponse sResponse;
   sResponse.status = AdblockPlus::WebRequest::NS_ERROR_FAILURE;
 
   if (method)
   {
-    jobject arrayList = NewJniArrayList(*env);
+    JniLocalReference<jobject> arrayList(*env, NewJniArrayList(*env));
 
     for (AdblockPlus::HeaderList::const_iterator it = requestHeaders.begin(), end = requestHeaders.end(); it != end; it++)
     {
-      JniAddObjectToList(*env, arrayList, NewTuple(*env, it->first, it->second));
+      JniLocalReference<jobject> tuple(*env, NewTuple(*env, it->first, it->second));
+      JniAddObjectToList(*env, *arrayList, *tuple);
     }
 
-    jobject response = env->CallObjectMethod(GetCallbackObject(), method, env->NewStringUTF(url.c_str()), arrayList);
+    JniLocalReference<jobject> response(*env, env->CallObjectMethod(
+        GetCallbackObject(),
+        method,
+        *JniLocalReference<jstring>(*env, env->NewStringUTF(url.c_str())),
+        *arrayList));
 
     if (!env->ExceptionCheck())
     {
-      sResponse.status = JniGetLongField(*env, serverResponseClass->Get(), response, "status");
-      sResponse.responseStatus = JniGetIntField(*env, serverResponseClass->Get(), response, "responseStatus");
-      sResponse.responseText = JniGetStringField(*env, serverResponseClass->Get(), response, "response");
+      sResponse.status = JniGetLongField(*env, serverResponseClass->Get(), *response, "status");
+      sResponse.responseStatus = JniGetIntField(*env, serverResponseClass->Get(), *response, "responseStatus");
+      sResponse.responseText = JniGetStringField(*env, serverResponseClass->Get(), *response, "response");
       // TODO: transform Headers
     }
   }
 
   CheckAndLogJavaException(*env);
 
   return sResponse;
 }
 
 jobject JniWebRequest::NewTuple(JNIEnv* env, const std::string& a, const std::string& b) const
 {
   jmethodID factory = env->GetMethodID(tupleClass->Get(), "<init>", "(Ljava/lang/String;Ljava/lang/String;)V");
-  return env->NewObject(tupleClass->Get(), factory, env->NewStringUTF(a.c_str()), env->NewStringUTF(b.c_str()));
+
+  JniLocalReference<jstring> strA(env, env->NewStringUTF(a.c_str()));
+  JniLocalReference<jstring> strB(env, env->NewStringUTF(b.c_str()));
+
+  return env->NewObject(tupleClass->Get(), factory, *strA, *strB);
 }
 
 static JNINativeMethod methods[] =
 {
   { (char*)"ctor", (char*)"(Ljava/lang/Object;)J", (void*)JniCtor },
   { (char*)"dtor", (char*)"(J)V", (void*)JniDtor }
 };
 
 extern "C" JNIEXPORT void JNICALL Java_org_adblockplus_libadblockplus_WebRequest_registerNatives(JNIEnv *env, jclass clazz)
 {
   env->RegisterNatives(clazz, methods, sizeof(methods) / sizeof(methods[0]));
 }